The word "vein" is often used to refer to the vessels that help circulate blood throughout the body. The specific job of a vein is to bring blood back to the heart. The word "vein is also used for plants.

Blood is drawn from a vein in your arm.

A phlebotomist is a person who draws blood from a vein.

How does a phlebotomist find a good vein from which to take blood?

Certain people can see veins on their arms, their hands, and on their feet.

Veins pop out when the flow of blood is restricted. (pop out = to be visible)

Some people are afflicted with varicose veins on their legs. Varicose veins indicate the potential for blood clots.